I saw on your tutorial video (https://youtu.be/l2ImHVgHhdM?t=491) that if there are two devices with the same tracks, Dropbox will merge them and duplicate tracks can occur. So this is intended behavior?
Is the following setup possible (while avoiding duplicate tracks):
1.) Use Lexicon for library management and Sync to Rekordbox (all done on my desktop).
2.) Use Dropbox Library Sync in Rekordbox (on my desktop) to backup my library (and to make it available on my gig laptop).
3.) Use my gig laptop only for gigging (I won't be using it for tasks like adding new tracks to Rekordbox - that will only happen on my desktop). This laptop should A.) sync (i.e. pull) from Dropbox, B.) create a local copy on the laptop (so I can gig without internet connection).